The two-prism experiment and wave-particle duality of light

A number of papers on wave-particle duality has appeared since the two-prism experiment was performed by Mizobuchi and Ohtake, based on a suggestion by Ghose, Home, and Agarwal. Against this backdrop, the present paper provides further clarification of the key issues involved in the analysis of the two-prism experiment. In the process, we present an overview of wave-particle duality vis-a vis Bohr's complementarity principle.     

Photoisomerization of merocyanine 540 in polymer-surfactant aggregate

Photoisomerization of merocyanine 540 (MC540) in a polymer-surfactant aggregate is studied using picosecond time resolved emission spectroscopy. The aggregate consists of the polymer, poly(vinylpyrrolidone) (PVP) and the surfactant, sodium dodecyl sulphate (SDS). With increase in the concentration of SDS in an aqueous solution of MC540 containing PVP, the emission quantum yield and lifetime of MC540 increase markedly. This indicates marked retardation in the nonradiative photoisomerization process of MC540, when it binds to the polymer-surfactant aggregate. The critical association concentration of SDS for binding to PVP has been found to be 0.5 mM. This is about 16 times lower than the CMC of SDS in pure water (8 mM).     

Guanine-rich RNAs and DNAs that bind heme robustly catalyze oxygen transfer reactions

Diverse guanine-rich RNAs and DNAs that fold to form guanine quadruplexes are known to form tight complexes with Fe(III) heme. We show here that a wide variety of such complexes robustly catalyze two-electron oxidations, transferring oxygen from hydrogen peroxide to thioanisole, indole, and styrene substrates. Use of (18)O-labeled hydrogen peroxide reveals the source of the oxygen transferred to form thioanisole sulfoxide and styrene oxide to be the activated ferryl moiety within these systems. Hammett analysis of the kinetics of thioanisole sulfoxide formation is unable to distinguish between a one-step, direct oxygen transfer and a two-step, oxygen rebound mechanism for this catalysis. Oxygen transfer to indole produces a range of products, including indigo and related dyes. Docking of heme onto a high-resolution structure of the G-quadruplex fold of Bcl-2 promoter DNA, which both binds heme and transfers oxygen, suggests a relatively open active site for this class of ribozymes and deoxyribozymes. That heme-dependent catalysis of oxygen transfer is a property of many RNAs and DNAs has ramifications for primordial evolution, enzyme design, cellular oxidative disease, and anticancer therapeutics.     

A testable prediction of the no-signalling condition using a variant of the EPR-Bohm example

Predictive power of the no-signalling condition (NSC) is demonstrated in a testable situation involving a non-ideal Stern–Gerlach (SG) device in one of the two wings of the EPR-Bohm entangled pairs. In this wing, for two types of measurement in the other wing, we consider the spin state of a selected set of particles that are confined to a particular half of the plane while emerging from the SG magnetic field region. Due to non-idealness of the SG setup, this spin state will have superposing components involving a relative phase for which a testable quantitative constraint is obtained by invoking NSC, thereby providing a means for precision testing of this fundamentally significant principle.     

Geometry of ‘standoffs’ in lattice models of the spatial Prisoner’s Dilemma and Snowdrift games

The Prisoner’s Dilemma and Snowdrift games are the main theoretical constructs used to study the evolutionary dynamics of cooperation. In large, well-mixed populations, mean-field models predict a stable equilibrium abundance of all defectors in the Prisoner’s Dilemma and a stable mixed-equilibrium of cooperators and defectors in the Snowdrift game. In the spatial extensions of these games, which can greatly modify the fates of populations (including allowing cooperators to persist in the Prisoner’s Dilemma, for example), lattice models are typically used to represent space, individuals play only with their nearest neighbours, and strategy replacement is a function of the differences in payoffs between neighbours. Interestingly, certain values of the cost–benefit ratio of cooperation, coupled with particular spatial configurations of cooperators and defectors, can lead to ‘global standoffs’, a situation in which all cooperator–defector neighbours have identical payoffs, leading to the development of static spatial patterns. We start by investigating the conditions that can lead to ‘local standoffs’ (i.e., in which isolated pairs of neighbouring cooperators and defectors cannot overtake one another), and then use exhaustive searches of small square lattices (4×4$4\times 4$ and 6×6$6\times 6$) of degree k=3,k=4$k=3,k=4$, and k=6$k=6$, to show that two main types of global standoff patterns–‘periodic’ and ‘aperiodic’–are possible by tiling local standoffs across entire spatially structured populations. Of these two types, we argue that only aperiodic global standoffs are likely to be potentially attracting, i.e., capable of emerging spontaneously from non-standoff conditions. Finally, we use stochastic simulation models with comparatively large lattices (100×100$100\times 100$) to show that global standoffs in the Prisoner’s Dilemma and Snowdrift games do indeed only (but not always) emerge under the conditions predicted by the small-lattice analysis.     

Two‐Dimensional Conducting Polymers: Synthesis and Charge Transport

Current technological advances and prolific endeavors have entrenched two‐dimensional conducting polymers as the rapidly emerging interface across a diversity of functional materials for flexible electronics, sensors, ion‐exchange membranes, biotechnology, catalysis, energy storage, and conversion. Rational design and fabrication of polymeric nanostructures enriched with well‐ordered geometry are appealing and endorse significant impact on their in‐built electrical, optical, and mechanical properties. In particular, recent interest in controlled hierarchical assembly of monomers/oligomers proved the free‐standing sheet‐like structures with exotic features of high conductivity and flexibility. Yet, the ongoing research to make nanometer‐thick polymers suffers from limitations to access large‐area, mechanical stability, and high‐range internal ordering. In this perspective, we focus on the radical approaches that highlight confinement‐entitled features of two‐dimensional polymeric materials correlating to their interface or template‐assisted synthesis, structure–property relationship, charge transport properties, and future scopes for relevant practical enactments. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1169–1176     

Bioactive Terpenoid from the Fruits of Lagerstroemia speciosa and its Molecular Docking Study

Chemistry of Natural Compounds - Bioactive terpenoids 1 and 2 along with a known compound, β-sitosterol, have been isolated from the DCM extract of the fruits of Lagerstroemia speciosa....     

Nonparametric tests for multistate processes with clustered data

Annals of the Institute of Statistical Mathematics - In this work, we propose nonparametric two-sample tests for population-averaged transition and state occupation probabilities for...     

Influence of a Halide Ion on Ribbons of Water Pentamer

Abstract  Reactions of CuF₂, CuCl₂ · 2H₂O and CuBr₂ with 2,2′-dipyridylamine (HDPA) in water at room temperature using Cu:HDPA = 2:1 mol yield [Cu(HDPA)(H₂O)₂F]F · 3H₂O (1), Cu(HDPA)Cl₂ (2) and Cu(HDPA)Br₂ (3) respectively. The structures of 2 and 3 are isostructural in spacegroup C2 with cell dimensions; for 2, a = 14.702(8), b = 7.726(2), c = 4.829(6) ?, β = 96.68(8)° and for 3, a = 14.2934(8), b = 7.9057(6), c = 5.1982(5) ?, β = 94.049(7)°. In the X-ray crystal structure, the complex 1 is found to contain tapes of water pentamers. Our DFT calculations at the B3LYP/LanL2DZ level show that the reaction Cu(HDPA)X₂ + 2H₂O = [Cu(HDPA)(H₂O)₂X]X is most exothermic in the gas phase when X⁻ = F⁻, i.e., the tendency of water uptake is maximum for Cu(HDPA)F₂. It seems that the exothermicities of the aquations of Cu(HDPA)Cl₂ and Cu(HDPA)Br₂ are not sufficient to stabilise the type of ribbons of water observed in 1 and consequently water is eschewed when X⁻ = Cl⁻ or Br⁻. Graphical Abstract  Cu(2,2′-dipyridylamine)X₂ takes up water to produce ribbons of water pentamer, as shown in the accompanied picture (red: O atom of a solvent water molecule), only when X⁻ is F⁻ but not when it Cl⁻ or Br⁻. The results are rationalised by means of DFT calculations at the B3LYP/LanL2DZ level. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.